We’ve been using Invoice Ninja for a few months now, but every month, we run into the same issue: The subscription needs to be renewed.
Hold on - let me finish! 
Once a customer pays through Invoice Ninja, we update a corresponding ticket in our helpdesk tool. We do that through Integromat, by watching the payments. That works fine!
However, every month the integration stops working, because of the payment. Hours pass until someone is awake and can re-activate the integration.
The root cause seems to be:
Monthly subscriptions expires - API access is revoked - the automatic renewal happens, charging the credit card - API access is granted again.
Thing is, in between that process, Integromat can’t access the API and the integration is deactivated.
If the process was like this:
Monthly subscription expires - trigger the credit card charge - (if payment unsuccessful:) revoke API access.
This whole thing could be avoided.